In recent years, an increasing number of distributed power supplies, such as a power generation apparatus using renewable energy (e.g., sunlight) and a storage battery, are used in electricity customers, and energy management systems for interactively controlling these components have been developed. There is a future need for a technology for not only controlling a distributed power supply under the control of an electricity customer using a single energy management system, but also enabling collaboration and cooperation between multiple energy management systems to perform electricity wheeling, including supply of excess electricity and compensation for electricity deficiency, depending on a varying amount of power supply or power consumption.
For example, Patent Literature 1 suggests an electricity wheeling apparatus that, upon an occurrence of electricity deficiency among multiple electricity customers, sends a wheeling request to other customers requesting an answer of the wheeling capacity value of that electricity customer, and calculates the amounts of wheeling electricity between electricity customers based on the requested amount of wheeling (hereinafter referred to as “wheeling request amount”) of that customer and on the wheeling capacity values of the respective electricity customers.